As far as how Mike ends up with that much money at the end is sort of a mystery. I agree that on the surface the math does not add up. If you recall however, when Mike wins the 10K and KGB talks him into playing again, as they are discussing raisings the blinds Mike says, "and feel free to reload at any time". I may not have the quote exactly right but you get the idea. Teddy may have gotten low on chips and got some more. Besides, they weren't paying a tournament. KGB could have brought more to the table for the second game for all we know. My point is that we are never really certain how much money was involved on KGB's side.

As far as why Grandma was pissed. I Think that there are two reasons. 1) Grandma was Worms "lacky" before worm went to prison. I think that Grandma bought up worms debt figuring on not betting paid. He just wanted to have leverage over worm and get worm in trouble with KGB (and the russian mob). It was a revenge thing. 2) Even though Grandma got paid back, it was really with his backers or partners money. His partner (KGB) being who he is, may or may not pay grandma. Actually Grandma probably borrowed KGBs money to buy worms debt. Grandma is really in a bad spot.